The effects of nickel in oxide layers on the AZ9I Mg alloys synthesized by plasma electrolytic oxidation

Abstract

The effect of nickel ion in electrolyte on the structural characteristics, surface color, and corrosion resistance were studied. The smaller size of pore could be observed on the oxide layer coated from electrolyte containing nickel ions, with which respond voltage increased on the higher rate compare to that from without nickel ions under constant applied current density. The color of oxide layer on AZ9I Mg alloy could be changed from light grey to moderate olive brown, when nickel ion added in electrolyte. The corrosion resistance was investigated with potentio-dynamic polarization analysis. The variation of corrosion current density and polarization resistance of oxide layer by adding nickel ions clearly indicated that incorporation of nickel could enhance the corrosion resistance of magnesium oxide layer synthesized with PEO proccs. which is strongly related with the change of microstructure of oxide layer by nickel oxide, which is added during PEO process.